/*

FUSE: Filesystem in Userspace

Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>

Minor modifications and note by Andy Sayler (2012) <www.andysayler.com>

Source: fuse-2.8.7.tar.gz examples directory

http://sourceforge.net/projects/fuse/files/fuse-2.X/

This program can be distributed under the terms of the GNU GPL.

See the file COPYING.

gcc -Wall `pkg-config fuse --cflags` fusexmp.c -o fusexmp `pkg-config fuse --libs`

Note: This implementation is largely stateless and does not maintain

open file handels between open and release calls (fi->fh).

Instead, files are opened and closed as necessary inside read(), write(),

etc calls. As such, the functions that rely on maintaining file handles are

not implmented (fgetattr(), etc). Those seeking a more efficient and

more complete implementation may wish to add fi->fh support to minimize

open() and close() calls and support fh dependent functions.

*/

#define FUSE_USE_VERSION 28

#define BUFSIZE 256

#define PAGESIZE 4096

#define CIPHER_BLOCKSIZE 128

#define AES_ENCRYPT 1

#define AES_DECRYPT 0

#define AES_PASSTHRU -1

#define HAVE_SETXATTR

#define ENCRYPTED_ATTR "user.pa4-encfs.encrypted"

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#ifdef linux

/* For pread()/pwrite() */

#define _XOPEN_SOURCE 500

#endif

#define _GNU_SOURCE

#include <fuse.h>

#include <stdio.h>

#include <stdlib.h>

#include <limits.h>

#include <string.h>

#include <unistd.h>

#include <fcntl.h>

#include <dirent.h>

#include <errno.h>

#include <sys/time.h>

#ifdef HAVE_SETXATTR

#include <sys/xattr.h>

#endif

#include <openssl/evp.h>

#include <openssl/aes.h>

#include "aes-crypt.h"

typedef struct {

char *rootdir;

char key[32];

char iv[32];

} xmp_state;

static char *_xmp_fullpath(char *buf, const char *path, size_t bufsize){

xmp_state *state = (xmp_state *)(fuse_get_context()->private_data);

snprintf(buf, bufsize, "%s%s", state->rootdir, path);

return buf;

}

static int xmp_getattr(const char *path, struct stat *stbuf)

{

int res;

char buf[BUFSIZE];

res = lstat(_xmp_fullpath(buf, path, BUFSIZE), stbuf);

if (res == -1)

return -errno;

return 0;

}

static int xmp_access(const char *path, int mask) {

int res;

char buf[BUFSIZE];

res = access(_xmp_fullpath(buf, path, BUFSIZE), mask);

if (res == -1)

return -errno;

return 0;

}

static int xmp_readlink(const char *path, char *buf, size_t size)

{

int res;

char pathbuf[BUFSIZE];

res = readlink(_xmp_fullpath(pathbuf, path, BUFSIZE), buf, size - 1);

if (res == -1)

return -errno;

buf[res] = '\0';

return 0;

}

static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,

off_t offset, struct fuse_file_info *fi)

{

DIR *dp;

struct dirent *de;

char pathbuf[BUFSIZE];

(void) offset;

(void) fi;

dp = opendir(_xmp_fullpath(pathbuf, path, BUFSIZE));

if (dp == NULL)

return -errno;

while ((de = readdir(dp)) != NULL) {

struct stat st;

memset(&st, 0, sizeof(st));

st.st_ino = de->d_ino;

st.st_mode = de->d_type << 12;

if (filler(buf, de->d_name, &st, 0))

break;

}

closedir(dp);

return 0;

}

static int xmp_mknod(const char *path, mode_t mode, dev_t rdev)

{

int res;

char buf[BUFSIZE];

_xmp_fullpath(buf, path, BUFSIZE);

/* On Linux this could just be 'mknod(path, mode, rdev)' but this

is more portable */

if (S_ISREG(mode)) {

res = open(buf, O_CREAT | O_EXCL | O_WRONLY, mode);

if (res >= 0)

res = close(res);

} else if (S_ISFIFO(mode))

res = mkfifo(buf, mode);

else

res = mknod(buf, mode, rdev);

if (res == -1)

return -errno;

return 0;

}

static int xmp_mkdir(const char *path, mode_t mode)

{

int res;

char buf[BUFSIZE];

res = mkdir(_xmp_fullpath(buf, path, BUFSIZE), mode);

if (res == -1)

return -errno;

return 0;

}

static int xmp_unlink(const char *path)

{

int res;

char buf[BUFSIZE];

res = unlink(_xmp_fullpath(buf, path, BUFSIZE));

if (res == -1)

return -errno;

return 0;

}

static int xmp_rmdir(const char *path)

{

int res;

char buf[BUFSIZE];

res = rmdir(_xmp_fullpath(buf, path, BUFSIZE));

if (res == -1)

return -errno;

return 0;

}

static int xmp_symlink(const char *from, const char *to)

{

int res;

char full_from[BUFSIZE];

char full_to[BUFSIZE];

res = symlink(_xmp_fullpath(full_from, from, BUFSIZE),

_xmp_fullpath(full_to, to, BUFSIZE));

if (res == -1)

return -errno;

return 0;

}

static int xmp_rename(const char *from, const char *to)

{

int res;

char full_from[BUFSIZE];

char full_to[BUFSIZE];

res = rename(_xmp_fullpath(full_from, from, BUFSIZE),

_xmp_fullpath(full_to, to, BUFSIZE));

if (res == -1)

return -errno;

return 0;

}

static int xmp_link(const char *from, const char *to)

{

int res;

char full_from[BUFSIZE];

char full_to[BUFSIZE];

res = link(_xmp_fullpath(full_from, from, BUFSIZE),

_xmp_fullpath(full_to, to, BUFSIZE));

if (res == -1)

return -errno;

return 0;

}

static int xmp_chmod(const char *path, mode_t mode)

{

int res;

char buf[BUFSIZE];

res = chmod(_xmp_fullpath(buf, path, BUFSIZE), mode);

if (res == -1)

return -errno;

return 0;

}

static int xmp_chown(const char *path, uid_t uid, gid_t gid)

{

int res;

char buf[BUFSIZE];

res = lchown(_xmp_fullpath(buf, path, BUFSIZE), uid, gid);

if (res == -1)

return -errno;

return 0;

}

static int xmp_truncate(const char *path, off_t size)

{

int res;

char buf[BUFSIZE];

res = truncate(_xmp_fullpath(buf, path, BUFSIZE), size);

if (res == -1)

return -errno;

return 0;

}

static int xmp_utimens(const char *path, const struct timespec ts[2])

{

int res;

struct timeval tv[2];

char buf[BUFSIZE];

tv[0].tv_sec = ts[0].tv_sec;

tv[0].tv_usec = ts[0].tv_nsec / 1000;

tv[1].tv_sec = ts[1].tv_sec;

tv[1].tv_usec = ts[1].tv_nsec / 1000;

res = utimes(_xmp_fullpath(buf, path, BUFSIZE), tv);

if (res == -1)

return -errno;

return 0;

}

static int xmp_open(const char *path, struct fuse_file_info *fi)

{

int res;

char buf[BUFSIZE];

res = open(_xmp_fullpath(buf, path, BUFSIZE), fi->flags);

if (res == -1)

return -errno;

close(res);

return 0;

}

static int xmp_read(const char *path, char *buf, size_t size, off_t offset,

struct fuse_file_info *fi)

{

FILE *f, *memstream;

int res;

char pathbuf[BUFSIZE];

char *membuf;

size_t memsize;

(void) fi;

f = fopen(_xmp_fullpath(pathbuf, path, BUFSIZE), "r");

memstream = open_memstream(&membuf, &memsize);

if (f == NULL || memstream == NULL)

return -errno;

char attrbuf[8];

ssize_t attr_len = getxattr(pathbuf, ENCRYPTED_ATTR, attrbuf, 8);

int crypt_action = AES_PASSTHRU;

if(attr_len != -1 && !memcmp(attrbuf, "true", 4)){

crypt_action = AES_DECRYPT;

}

xmp_state *state = (xmp_state *)(fuse_get_context()->private_data);

do_crypt(f, memstream, crypt_action, state->key);

fflush(memstream);

fseek(memstream, offset, SEEK_SET);

res = fread(buf, 1, size, memstream);

fclose(memstream);

if (res == -1)

res = -errno;

fclose(f);

return res;

}

static int xmp_write(const char *path, const char *buf, size_t size,

off_t offset, struct fuse_file_info *fi)

{

FILE *f, *memstream;

int res;

char pathbuf[BUFSIZE];

char *membuf;

size_t memsize;

(void) fi;

xmp_state *state = (xmp_state *)(fuse_get_context()->private_data);

f = fopen(_xmp_fullpath(pathbuf, path, BUFSIZE), "r");

memstream = open_memstream(&membuf, &memsize);

if (memstream == NULL)

return -errno;

char attrbuf[8];

ssize_t attr_len = getxattr(pathbuf, ENCRYPTED_ATTR, attrbuf, 8);

int encrypted = 0;

if(attr_len != -1 && !memcmp(attrbuf, "true", 4)){

encrypted = 1;

}

if(f != NULL){

do_crypt(f, memstream, (encrypted ? AES_DECRYPT : AES_PASSTHRU), state->key);

fclose(f);

}

fseek(memstream, offset, SEEK_SET);

res = fwrite(buf, 1, size, memstream);

fflush(memstream);

f = fopen(pathbuf, "w");

fseek(memstream, 0, SEEK_SET);

do_crypt(memstream, f, (encrypted ? AES_ENCRYPT : AES_PASSTHRU), state->key);

fclose(memstream);

if (res == -1)

res = -errno;

fclose(f);

return res;

}

static int xmp_statfs(const char *path, struct statvfs *stbuf)

{

int res;

char buf[BUFSIZE];

res = statvfs(_xmp_fullpath(buf, path, BUFSIZE), stbuf);

if (res == -1)

return -errno;

return 0;

}

static int xmp_create(const char* path, mode_t mode, struct fuse_file_info* fi) {

(void) fi;

(void) mode;

char buf[BUFSIZE];

FILE *res;

res = fopen(_xmp_fullpath(buf, path, BUFSIZE), "w");

if(res == NULL)

return -errno;

FILE *tmp = tmpfile();

xmp_state *state = (xmp_state *)(fuse_get_context()->private_data);

do_crypt(tmp, res, AES_ENCRYPT, state->key);

fclose(tmp);

if(fsetxattr(fileno(res), ENCRYPTED_ATTR, "true", 4, 0)){

return -errno;

}

fclose(res);

return 0;

}

static int xmp_release(const char *path, struct fuse_file_info *fi)

{

/* Just a stub. This method is optional and can safely be left

unimplemented */

(void) path;

(void) fi;

return 0;

}

static int xmp_fsync(const char *path, int isdatasync,

struct fuse_file_info *fi)

{

/* Just a stub. This method is optional and can safely be left

unimplemented */

(void) path;

(void) isdatasync;

(void) fi;

return 0;

}

#ifdef HAVE_SETXATTR

static int xmp_setxattr(const char *path, const char *name, const char *value,

size_t size, int flags)

{

char buf[BUFSIZE];

int res = lsetxattr(_xmp_fullpath(buf, path, BUFSIZE), name, value,

size, flags);

if (res == -1)

return -errno;

return 0;

}

static int xmp_getxattr(const char *path, const char *name, char *value,

size_t size)

{

char buf[BUFSIZE];

int res = lgetxattr(_xmp_fullpath(buf, path, BUFSIZE), name, value, size);

if (res == -1)

return -errno;

return res;

}

static int xmp_listxattr(const char *path, char *list, size_t size)

{

char buf[BUFSIZE];

int res = llistxattr(_xmp_fullpath(buf, path, BUFSIZE), list, size);

if (res == -1)

return -errno;

return res;

}

static int xmp_removexattr(const char *path, const char *name)

{

char buf[BUFSIZE];

int res = lremovexattr(_xmp_fullpath(buf, path, BUFSIZE), name);

if (res == -1)

return -errno;

return 0;

}

#endif /* HAVE_SETXATTR */

static struct fuse_operations xmp_oper = {

.getattr = xmp_getattr,

.access = xmp_access,

.readlink = xmp_readlink,

.readdir = xmp_readdir,

.mknod = xmp_mknod,

.mkdir = xmp_mkdir,

.symlink = xmp_symlink,

.unlink = xmp_unlink,

.rmdir = xmp_rmdir,

.rename = xmp_rename,

.link = xmp_link,

.chmod = xmp_chmod,

.chown = xmp_chown,

.truncate = xmp_truncate,

.utimens = xmp_utimens,

.open = xmp_open,

.read = xmp_read,

.write = xmp_write,

.statfs = xmp_statfs,

.create = xmp_create,

.release = xmp_release,

.fsync = xmp_fsync,

#ifdef HAVE_SETXATTR

.setxattr = xmp_setxattr,

.getxattr = xmp_getxattr,

.listxattr = xmp_listxattr,

.removexattr = xmp_removexattr,

#endif

};

int main(int argc, char *argv[])

{

umask(0);

xmp_state state;

if(argc < 4){

fprintf(stderr, "encfs usage: ./pa4-encfs %s %s %s\n",

"<Key Phrase>", "<Mirror Directory>", "<Mount Point>");

return 1;

}

state.rootdir = realpath(argv[2], NULL);

strncpy(state.key, argv[1], 32);

state.key[31] = '\0';

return fuse_main(argc - 2, argv + 2, &xmp_oper, &state);

}